Cold Weather May Help Prevent Soybean Disease

The colder the weather in winter, the better Louisiana soybean farmers like it. That's because freezing temperatures kill kudzu, a noxious plant that harbors the fungus responsible for Asian soybean rust.

Getting rid of kudzu as an over-the-winter host won't make Asian soybean rust go away, but it helps hold it at bay.

“Asian soybean rust is here to stay,” says Clayton Hollier, Louisiana State University (LSU) AgCenter plant pathologist. “We're learning the factors that promote and inhibit its development. That's a major research and Extension focus for the AgCenter.”

We were lucky in 2006, says David Lanclos, LSU AgCenter soybean specialist based at the Dean Lee Research Station in Alexandria. “Conditions in the spring were too dry for the disease to take hold,” he says.

Asian soybean rust likes warm, humid conditions — not too dry or hot, says Ray Schneider, LSU AgCenter plant pathologist. Schneider was the first to discover the disease in North America, in a soybean production field at the LSU AgCenter's research farm near Baton Rouge.

For 2007, the strategy is again scouting, planting sentinel plots and continuing with research to learn more about controlling the disease and developing resistant varieties.

“It helps to kill kudzu,” Lanclos says. “One strategy that growers will try to use this year is planting earlier-maturing beans.”

The only hopefor eventual elimination of the disease is the development of resistant varieties. To that end, Zhi-Yuan Chen, LSU AgCenter plant pathologist, is looking at soybean proteins of plants infected with Asian soybean rust and comparing them to proteins of uninfected plants.